Wind turbines create power proportional to the swept area of their blades. The choice of rotor attributes for a wind turbine, such as its diameter, is a design trade-off between longer blades for more energy production in low winds and shorter blades for load limitation in high winds. Thus, wind turbine having longer blades will increase the swept area, which in turn produces more power. However, at high wind speeds, a wind turbine having longer blades places greater demands on the components and creates more situations where the turbine must be shut down to avoid damaging components. Even in situations where the average wind speed is not high enough to cause damage, periodic wind gusts which change both the speed and direction of the wind, apply forces that may be strong enough to damage equipment.
Wind turbines also may generate sound or acoustics which can be disruptive to the surroundings. The sound may be caused by the vibration of components or airflow over the blades. The flow of air over the blades manifest sound or acoustics in various forms such as turbulence due to inflow, a turbulent boundary layer from the suction (top) and pressure (bottom) sides of the blade, flow separation, and the like.
In some wind turbine arrangements, deflectors are used to mitigate undesired wind turbine loading. However, the use of such deflectors may pose the penalty of increased wind turbine sound or acoustic levels.